1. Technical Field
The invention relates to container body forming presses for stamping metal can bodies from a strip of sheet metal in a succession of work stations in the press. More particularly, the invention relates to a transfer apparatus mounted in a fixed position on the base of the press between work stations for receiving and maintaining container bodies in a fixed position between work stations as the press is performing an operation on the adjacent can bodies at the work stations.
2. Background Information
It is well known in the container forming art to form two piece containers, that is, containers in which the walls and bottom of the container are a one piece member and the top end closure is a separate piece by stamping a plurality of blanks in a single or double action press from a strip of sheet metal and then subsequently drawing and redrawing the desired can body configuration into the blank in a series of work stations in the press.
These presses use multiple stage dies, that is, a single downward stroke of the press may simultaneously blank a plurality of disks from the sheet metal while at another station will draw the previously cut blank into a first stage can body while at still another work station in of the press the drawn can body will be redrawn into a final configuration or provide for a stepped shoulder or profile bottom thereto, with another station then trimming the annular outer flange of the can body to form the final container configuration. In these multiple station presses, a blank or dead space is generally provided between the work stations so that as the can body advances through the press it will rest in a dead space during each successive stroke while the press is performing a forming operation on the adjacent can bodies. Various mechanisms have been devised for sequentially moving the can bodies through the various stages of forming, that is, between the blank station to the redraw station to the shoulder and profile forming station, and then to the trimming station.
The prior art apparatus provided at the dead spaces between work stations usually will maintain the partially formed can body in position by applying a vacuum to the bottom of the body as it rests upon a transfer pad mounted in the dead space. This vacuum retention has proved satisfactory for prior art container bodies, especially those having a round bottom since the orientation of the body at the dead space always results in a similar shape bottom for gripping by the vacuum. However, more recently, various configured containers are being formed from the sheet metal other than a round container, one such example being a generally rectangular or elongated oval shaped container used for the storage of canned meat products such as sold under the trademark SPAM.RTM. and TREET.RTM.. The secure retention of these elongated can bodies on the transfer pads becomes more difficult due to the formation of a raised rib generally along only part of the can bottom which raises the majority of the can bottom wall off of the surface of the transfer pad making it extremely difficult for the suction of the vacuum to adequately hold the can against the pad surface due to the constant incoming of air through openings formed by the non continuous peripheral ribs or projections on the container bottom. The proper retention of the container bodies on the transfer pads becomes increasingly important and more difficult to satisfactorily achieve with the non circular shaped container bodies due to the ever increasing speed of the press and resulting transfer of the container bodies between the various work stations.
Therefore, the need exists for an improved transfer pad located at the transfer or dead areas of a multiple station press for securely gripping and positioning non circular container bodies thereon.